J Integr Plant Biol. ›› 2011, Vol. 53 ›› Issue (9): 698-709.DOI: 10.1111/j.1744-7909.2011.01059.x

Special Issue: Rice Genomics and Agriculture

• Cell and Developmental Biology •     Next Articles

Adenosine Diphosphate Ribosylation Factor-GTPase-Activating Protein Stimulates the Transport of AUX1 Endosome, Which Relies on Actin Cytoskeletal Organization in Rice Root Development

Cheng Du1,2, Yunyuan Xu1, Yingdian Wang2 and Kang Chong1*   

  1. 1Key Laboratory of Photosynthesis and Molecular Environmental Physiology, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
    2College of Life Sciences, Beijing Normal University, Beijing 100875, China
  • Received:2011-05-10 Accepted:2011-05-24 Published:2011-06-01
  • About author:*Corresponding author. Tel: +86 10 6283 6517; Fax: +86 10 8259 4821; E-mail: chongk@ibcas.ac.cn


Polar auxin transport, which depends on polarized subcellular distribution of AUXIN RESISTANT 1/LIKE AUX1 (AUX1/LAX) influx carriers and PIN-FORMED (PIN) efflux carriers, mediates various processes of plant growth and development. Endosomal recycling of PIN1 is mediated by an adenosine diphosphate (ADP)ribosylation factor (ARF)-GTPase exchange factor protein, GNOM. However, the mediation of auxin influx carrier recycling is poorly understood. Here, we report that overexpression of OsAGAP, an ARF-GTPase-activating protein in rice, stimulates vesicle transport from the plasma membrane to the Golgi apparatus in protoplasts and transgenic plants and induces the accumulation of early endosomes and AUX1. AUX1 endosomes could partially colocalize with FM4–64 labeled early endosome after actin disruption. Furthermore, OsAGAP is involved in actin cytoskeletal organization, and its overexpression tends to reduce the thickness and bundling of actin filaments. Fluorescence recovery after photobleaching analysis revealed exocytosis of the AUX1 recycling endosome was not affected in the OsAGAP overexpression cells, and was only slightly promoted when the actin filaments were completely disrupted by Lat B. Thus, we propose that AUX1 accumulation in the OsAGAP overexpression and actin disrupted cells may be due to the fact that endocytosis of the auxin influx carrier AUX1 early endosome was greatly promoted by actin cytoskeleton disruption.

Du C, Xu Y, Wang Y, Chong K (2011) Adenosine diphosphate ribosylation factor-GTPase-activating protein stimulates the transport of AUX1 endosome, which relies on actin cytoskeletal organization in rice root development. J. Integr. Plant Biol. 53(9), 698–709.

Key words: actin, adenosine diphosphate ribosylation factor-GTPase-activating protein, AUX1, endosome, polar auxin transport

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